If the ‘Innocence of Muslims’ started as an amateur film shot in California’s inland empire, it ended as a subject of international violence, requiring the U.S. Secretary of State herself to denounce it.

It’s the flip side of the sea change that social media tools have brought to modern culture and politics – the dark side of Facebook, YouTube and Twitter.

We have watched how social media has empowered individuals shut out of power in dictatorships, and this historic shift, made possible by the likes of Mark Zuckerberg, Chad Hurley and Jack Dorsey, has been a stunning thing to observe.

When it came to the Facebook revolution in Egypt, social media allowed for a handful of people to amplify their long-simmering anger toward their government and leverage that into a revolution that toppled the reign of Hosni Mubarak.

But the fatal trajectory of Nakoula Basseley Nakoula’s laughable YouTube farce (pictured as deputies take him for interview, Nakoula was not held/ Getty) reminds us that social media holds a dark power too. In this case, the tools of new media were used to manipulate and disseminate a low-grade video that should never have gotten a shred of attention, much less incite a pan-regional mob.

The digital-age gift of rendering the world transparent, creating instant communication everywhere, means that false messages, or ones with evil intent, can also spread in a heartbeat — take root, gain momentum and become adopted as fact before anyone can denounce them as lies or manipulation.

This should give us all pause. I somehow doubt that in the giddy aftermath of the Arab spring, the leaders of social network companies gave much thought to the dangers on the flip side. Speaking last year at the Paley Center, Facebook COO Sheryl Sandberg described a digital utopia, led by Facebook.

“This is about engagement. This is about giving people an authentic voice and what happens as a result,” Sandberg said, referring to the social change in everything from Arab politics to organ donations.

The awesome power of social media puts freedom of speech on steroids, and makes it the communication equivalent of nuclear power.

And like actual nuclear power, once discovered as a tool, it can hardly be ignored. Now that one person succeeded in his goal of inciting Muslims with crude insults (and again, we don’t know who translated it into Arabic, and how it happened to be widely seen on Sept. 11, hardly a coincidence), it is an open invitation for any extremist with a Youtube account to do the same.

How should we respond? Can we put the social media genie back in the bottle?

I doubt it. It is out. It is driving history.

We must embrace Facebook and Twitter for the historic forces that they represent — flattening the former hierarchy in mass communication, and collapsing those messages into real time. And we must rededicate ourselves to restraint, respect and responsibility in using those tools.

But we need to go further. If shouting “Fire” in a crowded theater represents the legal limit of the First Amendment, then we must actively consider what the equivalent of that is in the digital age.